Flow proportioning apparatus



mmh 2s, 1944.

H. zlEBoLz 2,345,520.

FLOW PROPORTIONING APPARATUS vFiled July 9, 1941 Patented 28, 1944 l ENT OFFICE FLow PnoPon'noNlNG APPARATUS Herbert Ziebolz, Chicago, Ill., assigner to Askania Regulator Company, Chicago, lll., a corporation of Illinois Application July 9, i941-, serial No. 401,656

' 1l claims( (ol. 131-7-164) This'invention relates to improved apparatus for controlling the ilow of combustion supporting air to a furnace.

Heretofore, it has been suggested that rates of fuel flow be summarized by means of fuel ow meters or by pilot air-ows which are directly proportional to the individual B. t. u. rates of fuel ow and the total air proportioned to the sum of the individual fuel flows in terms of their heating values. I'he design of such mechanisms is based on the fact that a definite amount of air is required for theoretically complete combustion of a given quantity of fuel in terms of its B. t. u. value. In the operation of industrial furnaces or boiler furnaces a number of factors must `be taken into consideration which render the supply of the calculated or exact amount of air necessary for theoretically complete combustion, improper. Such factors do not vary as a direct f function of the rate of fuel flow but present different values at different rates of fuel ilow.` Some of these factors are, for example, air used to atomize liquid fuels or primary air used for conveying pulverized fuel, which air is not subject to control by the well known air control apparatus.' Such factors may be termed .bumer factors." The calculated amount of air, which would'be supplied by the control apparatus to support theoretically complete combustion of a single fuel, modified by the amount of air which finds its way.v into the burner installation by reason of these factors, is referred to herein as "compensated air requirements of that fuel. If

more'than one fuel is supplied, the calculated amount of air which would be supplied by the control apparatus to support theoretically complete combustion'of the plurality of fuels, modifled b3" the a'mount of air which finds its way into the, burner installation, as a result of the feeding of more than one fuel, is referred to herein as "totalizer compensated air requirements" for the fuels. Further correction factors may be necessary in any furnace installation to take into ac- It is therefore the main object of this invention to provide improved apparatus of the above type which will adjust the controlled supply of combustion air in accordance with varying fuel flow and other variable factors, such as those mentioned above.

Other aims and advantages of the invention will'appear in the specification, when considered in connection with the accompanying drawing, wherein:

' Fig. 1 is a diagrammatic illustration of a summarizing mechanism embodying the invention and applied to two uid fuels;

Fig. 2 is a top plan view of diiferential gearing of the type employed in-Fg. 1; and

Fig. 3 isa diagrammatic illustration showing differential gears applied to the control of three fuels. Referring particularly to the drawing, the apparatus .there shown is applied to control the amount of combustion supporting air for separate fluid fuels, each of which is manually controlled and is subject to variations in quantity flow. In Fig. 1 there are shown two fuel conduits l0 and ll and a single air conduit l2 through which air is supplied for the combustion of both fuels. All of the conduits lead to an ordinary furnace (not shown). Reference is here made to a patent to Ziebolz et al. No. 2,134,745, wherein regulators are employed to proportion the flow of air to the iiows of a pluralityl of separate fuels.

count infiltration-lof air into the furnace, other sources of air of determinable amounts admitted to the furnace, or the desired condition of the furnace atmosphere. of these factors are subject to variations which are not direct functions of the rate of total fuel supply. 'I'hey may be termed furnace factors.4 These furnace factors may require further adjustment in the "total compensated air requirements" called for by the fuels. The total compensated air requirements, thus modied by these furnace factors, is herein termed adjusted total air requirements." 6o

In the present instance, differential pressure ow impulses are produced on opposite sides of restrictions in the-fuel lines. These pressure differentials are transformed into movements which are directly proportional to the respective compensated amount of air for the fuels atdiiferent rates of now. These movements, which do not have to be directly proportional to the B. t. u.

rates of ow, are transmitted to a summarizing device connected to control the .flow of air.

Herein, each of theconduits I0 and Il has a constriction I3, on the opposite sldesof which, are

connected pipes I4 and I5 leading to the opposite sides of a diaphragm I6 connected to act on one side of a pivoted jet pipe l1 of av differential pressure operated regulator of a well known type. 'Ihe force exerted by the diaphragm -acts in opposition to a spring I8, the compression of which is controlled by a cam I9 of adjustable contour. Herein, the cam is shown as being composed of a multiplicity or relatively adjustable, slotted pieces clamped together by a bolt i2|) andsecured t0 a carriage 2| which is slidably mounted in 2. xed bearings. The jet pipe regulator hasan ordinary ratio slider 22 which may be employed to vary the ratio between the compensated air requirements for the fuel and the fuel ow, as will be described. The jet pipe is shown as delivering uid to one or the other of two conduits 23 and 2l connected to crate a servo motor 25 of the piston type which, in turn, operates a gear 26 meshing with a rack 21 on the carriage 2l. The carriage is shown as carrying a pointer 28 cooperating with an indicating scale 29 which indicates the compensated individual air requirements for the fuel, as called for by the carriage movements.

It will be seen that aA force exertedby the diaphragm I6 on the. jet pipe relay will move the jet pipe until the servo-motor operates the cam I9 and compresses spring I8 sumciently to counterbalance thecactlon oi.' the diaphragm force and returns the jet pipe toits neutral position. Thus, -a denite relation between the now impulses and the movement of the cam, indicated by pointer 28, is established. This relation can be changed by varying the contour of the loading cam to compensate for varying factors which affect the burner performance, such as atomizing or primary air delivered with the fuel or air seepage into the fuel conduits and the burner. such air may be delivered at a constant rate or may vary out of proportion to changes in the iuel load or ratesl of ow. The cam is thus adjusted to cause .n the impulse system to produce movements which Y are directly proportional to the compensated air requirements necessary to support complete combastion oi the fuel at varying rates of now but ignoring air tration through the furnace walls or the particular characteristic of the furnace;

From the above, it will be apparent that, regardless of the characteristic oi a dow impulse which, in many cases, is not a second power iunc- .tion, it is always possible to produce Va corresponding movement oi the cam i9 which is directly proportional to the compensated air requirements of the individual fuels for a given rate of ovv. More particularly, this arrangement permits adjustments to be made which take into account the burner characteristics and the amount of air delivered with the fuel at any rate of iiring. For example, some burners require a constant amount of primary or atomizing air and others require amounts which are out of proportion to the fuel. load. 'These conditions can be anticipated by means oi the variable cams IQ. In addition, the ratio sliders a2 permitV the introduction of correction factors which take into account variations in the chemicalanalysis of the fuels, viscosity changes, density changes, temperature changes, etc. Any change in the position of the ratio sliders 2d increases or decreases the stroke of the cams directly proportional to the impulses throughout the rlow ranges.

-In the present instance, the movements of the cams, which are proportional to the compensated nir requirements 'of the duels, are transmitted through a summarizing device to a control valve for the air. Herein. each rack is shown as carryinga iixed arm 3@ to which is pivotally conlar to cams i9. This cam is shaped to take into account total air infiltration into the furnace nected an operating link di. The operating links f to 'a gear 3l. The gear :i operates a rack member or carriage 88, which is similar to the carriages 2i and carries an adjustable dem 39 Simi- .air may be changed at will.

and to vary the total compensated supply of air called for by the fuels under varying total fuel loads. It is also used to allow for either an excess or a deciency oi air throughout the fuel load range when the percentages of excess or deficiency are not directly proportional to the load. Further, it can be adjusted to allow for combustible gas generated in a furnace reaction calling for more air at dierent fuel loads. Likewise, v

it can allow -for uncontrolled air delivered to the furnace from another source. In fact, the adjustment of this cam greatly inuences the furnace operation or program. The carriage 38 is :mounted similarly to the carriages 2i and is also shown as carrying a pointer 40 cooperating with a scale di, to indicate the sum or" the compensated air requirements of the separate fuels in addition to the compensation added by varying cam 59, because the movement imparted to the gear 31 and, through it, to the cam 39 represents the sum of the movements imparted by the separate cams through the dierential gear.

Now, the flow voi' the air in conduit i2 is shown as being controlled by a buttery valve 52 which is actuated by a piston type servo-motor 133. The servo-motor is connected by pipes d4 and 45 to be operated by a jet pipe 46, 'also having a ratio slider di, whereby the ratio between the amount of air called for by the totalizing cam and the actual or the adjusted total amount of controlled The cam 35i acts on one side of the jet pipe through a spring d8 and changes the setting of the regulator to control the air flow through conduit i2. The spring 48 acts on the jet pipe in opposition to a diaphragm d@ on the opposite side of the jet pipe, and the position of the diaphragm ,is controlled by the'pressure differential across a constriction E@ in the air conduit, acting through pipes 5i and 52 on opposite sides of the diaphragm.

As the spring d8 is compressed by the movement of the cam 3d to the right, the jet pipe turns clockwise and thereby causes the servorn'otor to open the valve 42 until the increase in air flow creates a diierential pressure across the constriction 5d which is sucient to counterbalance the spring pressure. Thus, the air'ow is so controlled that it is proportional to the air cam movement, which-in turn, is directly proportional to the sum of the individual compensated air requirements of the individual fuels. as further modified by the adjusted contour of cam 3d. The adjustments of the ratio slider #il permit variations in the ratio between the air now called for by the cam 39 and the actual air now, thus controlling the percentage oi' excess or deciency of the total air.

As the now of iuel i increases, for example, it

will be understood that the regulator and the' mechanism will impart movement to the leithand link si and crankV 32v to the right and, as

yoperate the piston of the servo-motor La in a direction to open the valve d2 and thereby increase the riow of air. Then, the resistance to movement ofthe jet pipe is increased by an increased dierential pressure acting on the dlaphragm tu. When the dierential pressure @those shown for the two links 3| in Fig. 1. `will be understood that any number of fuels may counterbalances the spring pressure, the jet pipe automatically returns to its neutral position.

In Fig, 3 there is shown an arrangement of differential gears for transmitting summarizing movements in accordance with the compensated air requirements for three fuels. In that instance, the summarizing shaft 36 is connected to operate one of the two spur gear shafts 33 of the second differential gearing which has a differential gear shaft 36 carrying the gear 31. The other shaft 33' of the second dierential gearing is connected to be operated by a link 3| which is actuated in response to the compensated air requirementsV for the third fuel. 'The operatingmeans for the third link 3|' may be similar to It be handled in this manner by adding to the num*- ber of differential gears. Furthermore, the mechanism will function satisfactorily if only one fuel is used at any given time.

Referring again to the mechanism shown in Fig. 1, it will be understood that the regulators, servo-motors and the cams may be mounted on any suitable support, such as a table. The stroke of the cams can be made the same for all controls by choosing the necessary gear ratios of the differential gears and the cams may be guided for straight line movement in any convenient manner, for example, by wheeled or sliding carriages or the like. Moreover, the compensated air requirement indicators may be either mechanical or electrical and all of' them may be located at any convenient point.

,Obviously, the present invention is not restricted t'o the particular embodiment thereof herein shown and described. Moreover, it is not indispensable that all the features of. the invention be used conjointly, since they maybe employed advantageously in various combinations and sub-combinations.

What is claimed is:

1. Apparatus for proportionng and controlling the supply of combustion air for at least two separate fuels which are subject to varying fiows, comprising, in combination, individual conduits for the air and the respective fuels; means for producing controlling impulses respectively responsive to the rate of flow of each of the fuels; impulse operated systems, including movable elements and associated adjustable means, so connected as to produce movements of said elements which are directly proportional to predetermined amounts of air corresponding with diiferent rates of fuel flow and theoretically necessary to support complete combustion of the fuels in the burner installation, said adjustable means being arranged to effect a departure from the proportional relation between said movements and the rates of fuel flow by a predetermined amount for each increment of change in the rate of fuel flow; a vsummarizing device connected to said movable elements to totalize said movements; control means for adjusting the supply of air through said air conduit connected for actuation by operation of said summarizing device; and means; forming a part of said air control means, to alter the effect of the operation of said summarizing device, said altering means being constructed and arranged to produce any predetermined, desired variation in the flow of airl through said conduit, as effected by operation of vsaid summarizing device for each increment of its y total movement, whereby predetermined atmos- 2. Apparatus for proportioning and controlling the supply of combustion air for any number of separate fuels comprising, in combination, individual conduits for the air and the respective fuels; means connected to the respective fuel conduits to produce impulses which are functions of the rates of the fuel ows; impulse operated systems, including movable control elements and lassociated manually adjustable means, so connected as to convert said impulses into controlling movements which are directly proportional to compensated air requirements which would support complete combustion of the respective fuels at varying rates of ow, said manually adjustable means being constructed and arranged to effect a departure from the proportional relation between said movements and the rates of fuel flow by a predetermined amount for each increment of change in the rate of fuel flow; summarizing means connected to said control elements; and

air control means connected to be operated in response to the sum of said controlling movements transmitted through said summarizing Ithe rates of-the fuel flows; impulse operated systems, including movable control elements and associated manually adjustable means, so connected as to convert said pressure impulses into controlling movements which are directly proportional to the compensated air requirements which would support complete combustion of the respective fuels at varying rates of fuel flow, said manually adjustable means being constructed and arranged to effect a departure from the proportional relation between said movements and the rates of fuel ow by a predetermined amount for each increment of change in the rate of fuel flow; differential gearing connected to said control elements to summarize said proportional movements; and air control means connected to be operated by said differential gearing in response to the summarized movements transmitted therethrough.

4. Apparatus as set forth in claim 1, wherein the impulse operated systems include fluid jet pipe regulators controlled by the impulses and the manually adjustable means comprises a loading cam of adjustable contour for each regulator connected to operate the control elements.

5. Apparatus as set forth in claim 1, wherein the impulse operated systems include fluid jet pipe regulators controlled by the impulses and servo-motors, operated by the regulators, are connected to transform the impulses into the movements, each regulator having ratio controlling means to vary the ratio between the fuel flows and the movements to take into account changes in the character of the fuels, such as the B. t. u. content, temperature, viscosity and other factors which vary in proportion to the fuel pheric conditions in a furnace may be obtained.

flows.

6. Apparatus as set forth in claim l, wherein the impulse operated systems include servomotors connected to said movable elements and indicators are associated 'with said elements to indicate amounts of air corresponding with and called for by said movements.

7. Apparatus as set forth in claim 1, wherein the summarizing device comprises differential 4 ascenso gearing Connected to the movable elements, and the air control means includes a iluid iet pipe regulator which varies the supply oi air delivered by the air conduit-and the means to alter the effect of the operation oi said summarizing device is a movable loading cam of adjustable contour operated by the erential gearing to control the regulator, the adjustments of said cam taking into account air inltration into the furnace.

8. Apparatus as set forth in claim l, wherein the summarizing device comprises erential gearing connected to the movable elements, and the air control means includes a rlud jet pipe regulator which varies the supply of air delivered by the air conduit and the means to alter the efrect of the operation of said arizing device is a movable loading cam of adjustable contour,

operated by the diuerential gearing to control the regulator, and the regulator has a ratio varying element, the contour of the cam taking into account any uncontrolled air delivered to the furnace andthe ratio varying element providing ior any desired percentage of excess `or dellciency oi controlled air throughout the total fuel load range. Y

9. Apparatus as set forth in claim l, wherein the air control means includes a uid jet pipe regulator and the altering means is a loading cam of adjustable contour for the regulator connected to be operated by said summarizing device; and a ratio varying device is also associated with said regulator.

lo. En apparatus of the class described for proportioning and controlling tl'ie supply of combustion airiin accordance with a varying supply of uicl fuel, means connected to produce controlling impulses in response to varying rates of fuel iiovv; an impulse operated system, including a movable element, coected to produce movements of said element in response to changes in l the rate ol iuel new which are directly proportional to predeteed amounts of air corresponding with erent rates of fuel iiow and theoretically necessary for complete combustion of the iuel at said dow rates; manually adjustable means, io o 1 i: a part oi d impulse system, to

said proportional relation between the movements and fuel ovv at erent rates and constructed and arranged to take into account iactors which are not proportional to the iluel at diiferent rates of fuel flow, such as air enti-aimed with the fuel; means for supplying air through a conduit to burn the fuel; control means for varying the supply of air through said conduit connected to be actua by said movable element; and means, iorg a part of said air control means, to alter the eiect of the operation of said movable element, said altering means being 'constructed and arranged to produce any predetermined desired variation in the ow of air through said conduit, aseected by operation oi the movable element, for each increment of its total movement.

1l. Apparatus for proportioning the now of one uid relative to a function oi the ow of at least two additional fluids comprising, in combination, individual conduits for the fluids; means connected to the conduits for said additional uids to create impulses which represent a function of the respective additional uid flow rates; an impulse operated system, including movable elements, connected to said impulse means for each additional duid now to convert said impulses into movements oi said elements which represent a function of but not necessarily directly proportional to the magnitude oi the im- A pulses; summarizing means connected to said last named means; and a hydraulic jet pipe regulator having a loading cam and being connected to control the ow of said rst mentioned duid, 

